Pump



E. R. PIERCE March 22, 1960 PUMP Filed Deb. so, 1954 2 Sheets-Sheet 1ATTORNEY March 22, 1960 E. R. PIERCE 2,929,332

- PUMP Filed Dec. 30. 1954 2 Sheets-Sheet 2 INVENTOR ATTORNEY UnitedStates Patent "cc Motors Corporation, Detroit, Mich., a corporation ofDelaware Application December 30, 1954, Serial No. 478,765

13 Claims. (Cl. 103-148) The present invention relates to pumps and moreparticularly to pumps especially adapted for supplying fuel to internalcombustion engines.

In the operation of internal combustion engines of the spark ignitedtype, the fuel is atomized and mixed with air to form a combustiblecharge. Usually the atomization and mixing occur in a carburetor and thecharge is carried to the combustion chamber by an intake manifold. Undersuch circumstances, the fuel par ticles frequently precipitate out ofthe charge. As a result the fuel economy and the performance of theengine may be improved by injecting the fuel into the air as close tothe combustion chamber as possible. This may be accomplished byemploying a plurality of fuel nozzles each of which is disposed adjacentan intake valve and is supplied by a fuel pump. In engines of the sizenormally employed in automotive vehicles, the quantity of fuel injectedduring each cycle is very small especially when the engine is operatingat or near idle conditions. Thus the pump employed must have a verysmall capacity. As a consequence the various parts of the pump requiresuch a large amount of precision machining that the cost has discouragedthe use of such systems on mass produced automobiles.

It is now proposed to provide a pump which is particularly adapted foruse on an internal combustion engine while at the same time it will beeconomical to manufacture and reliable in operation. The pump mayinclude a cylinder and a piston reciprocably disposed therein. One endof the cylinder may be open so that the piston may be reciprocablydriven therethrough. The opposite end of the cylinder may be closed andhave a resilient plug disposed therein. This plug may be compressed inits position so that it will positively engage the end of the piston,the side walls of the cylinder, and the end wall of the cylinder. Apumping chamber may be formed in the end of the cylinder by a recess inthe end of the plug and/or the cylinder end wall. One or more passagesmay be provided which will communicate with this chamber to form theinlet and outlet of the pump. The inward movement of the piston willcompress the plug and cause the volume of the pumping chamber todecrease and force the liquid therefrom. When the piston moves outwardlythe plug will expand and draw a fresh supply of fluid into this chamber.

By placing the pumping chamber in the end of the cylinder, any fiuidescaping between the working parts of the pump must pass between theplug and the cylinder walls. Since the plug is resiliently deformable itwill tightly engage all portions of the cylinder wall and prevent theescape of any fluids. In addition, when the liquid is under the mostpressure, the plug will be compressed and thus be forced against thecylinder walls more tightly. This will in turn improve the sealingaction and prevent the liquid escaping. As a result the clearance spacebetween the piston and cylinder will not form a part of the seal andthus reduce the tolerances required in producing the parts.

The capacity of the pump will be determined by the capacity of thepumping chamber, and the capacity of this chamber may be controlled bythe size of the recess in the plug and/or the end wall of the cylinder.Thus the pump capacity may be altered without changing the bore orstroke. It is therefore apparent that a small capacity pump may be madewithout necessitating the use of extremely small precision parts.

In the two sheets of drawings:

Figure l is a view of a pump structure employing the present invention,portions of the pump being broken away.

Figure 2 is a fragmentary view of a pump similar to that in Figure 1 butemploying a modified form of the present invention.

Figure 3 is a fragmentary view of a pump similar to that in Figure 1 butemploying a modified form of the present invention.

Figure 4 is a fragmentary view of a pump similar to that in Figure 1 butemploying a modified form of the present invention.

Figure 5 is a fragmentary view of a pump similar to that in Figure 1 butemploying a modified form of the present invention.

Figure 6 is a fragmentary view of a pump similar to i that in Figure 1but employing a modified form of the present invention.

Figure 7 is a fragmentary view of a pump similar to that in Figure 1 butemploying a modified form of the present invention.

Figure 8 is a fragmentary view of a pump similar to that in Figure 1 butemploying a modified form of the present invention.

Referring to the drawings in more detail the present invention may beembodied in any suitable pump 10. In the present instance the pump 10may be disposed in a casing 12 having other similar pumps mountedtherein, each of which is adapted to pump fuel to one or more cylindersof an internal combustion engine as shown. in copending applicationsSerial No. 511,954 on Fuel Injection System by John Dolza, now PatentNo. 2,890,- 690 and Serial No. 512,448 on Fuel Injection Pump by JohnDolza, now abandoned.

The casing 12 may have a plurality of walls 14 that are secured togetherto form a compartment 16 that encloses a rotating cam 18 driven by theengine and having an eccentric periphery 20.

The pump 10 comprises a housing 22 having a barrel portion 24 and anenlarged end portion 26. The end portion 26 may form a flange 28 thatengages one wall 14 of the casing 12 while the barrel portion 24 pro-'jects through an opening 30 in the Wall 14 into the compartment 16inside the casing 12. The pump 10 may be secured in this position by anysuitable means such as bolts. The barrel portion 24 which projects intothe compartment 16 has the inner end thereof adjacent the cam 18.

A passage 32 may extend into the barrel portion 24 with one end thereofforming an opening 33 in the inner end of the barrel portion 24. Thispassage 32 may have a generally cylindrical side Wall 34 and an end wall36 that is disposed normal to the axis of the passage 32. A plunger orpiston 38 may be disposed in the cylindrical passage 32 with the outerend project-- the barrel portion to form inlet and outlet openings 42and 44, respectively, in the opposite sides of the barrel portion 24.This passage 40 may be interconnected with the cylindrical passage 32 bya small pas- Patented Mar. 22, teen sage 46 that intersects the centerof the supply passage 40 and also forms an opening 48 in the center ofthe end wall 36. Inlet and outlet passages 50 and 52 may be formed inthe casing 12.so as to communicate wtih the inlet and outlet openings 42and 44 in the opposite sides of the barrel portion 24. The inlet passage50 may be connected to a source of liquid such as a fuel tank, while theoutlet passage 52 may be adapted to discharge the liquid into anysuitable device suchas a nozzle.

Inlet and outlet valves 54 and 56, respectively, may be provided tocontrol the flow of liquids into and out of the pump 10. The presentinlet valve 54 is disposed in the supply passage and it includes a platebiased to seat on a valve insert by a spring. The outlet valve 56 isdisposed in the outlet passage 52 and is similar to the inlet valve andincludes a plate biased. to seat on a valve insert by a spring.

A plug 58 of resilient material may be provided in the closed end of thecylindrical passage 32 so as to engage the plunger 38 and the end wall36 of the cylindrical passage 32. This plug 58 is preferably] of aresilient material which is easily compressible but which is elasticenough to immediately return to its original shape when released. Thediameter of the plug 58 is preferably equal to or slightly larger thanthe diameter of the cylindrical passage 32 so that the plug 58 willfirmly engage the side walls 34' of the passage 32.

creases, the plunger 38 will move inwardly and further compress'the plug58. As this rotation continues and the cam lift decreases, the plug 58will expand and move the plunger 38 outwardly thereby retaining theplunger 38 against the cam periphery 20 at all times.

The end of the plug 58 may have a recess 60 provided in the end whichengages the end wall 36. This recess 60 may cooperate with the end wall36 to form a pumping chamber. This chamber may be of any desired shapebut in the present embodiment, it is a semi-spherical shape and ispreferably positioned to register with the opening 48 formed by thepassage 46. The recess is substantially the same diameter as the passage46. When the cam 18 is rotating so that the lift is increasing, theplunger 38 will be forced into the cylinder 32. This will'tend tocompress the plug 58 andcause the plug material to flow into the pumpingchamber and decrease the volume thereof. Thus if there is any fluid inthe chamber, it will be forced to flow from the chamber into the supplypassage 40 and out through the outlet valve 56. As the cam 18 continuesto rotate and the lift decreases the resilient action of the plug 58will cause the plug 58 to expand and retain the plunger 38 against thecam 18. At the same time the expansion of the plug 58 will allow theplug 58 to return to its original shape; thus the pumping chamber willregain its original capacity. Consequently, the fluid will be drawnthrough the inlet valve 54 into the pumping chamber so the cycle can berepeated.

Before any fuel can escape from the pumping chamher, it must leakthrough the space between the cylindrical side walls 34 of the passage32 and the exterior of the plug 58. However, since the plug 58 isresilient it will tightly engage the side walls 34 even if there aresome irregularities therein. Thus an effective seal will be provided. Itshould be noted that when the pressure in the fluid is high, the plug 58will also be highly compressed thereby increasing the sealing action atthis time. By providing a small amount of taper 59 in the side walls 34of the cylinder 32 adjacent its inner end, the lateral pressure betweenthe plug 58 and cylinder Thus the plug 58 will' 4' 32 may be evenfurther increased, especially if the plug 58 has a cylindrical exterior.

It will thus be seen that an etfective seal will be pro vided betweenthe plug 58 and the cylinder wall 34. Therefore the space between theplunger 38 and the side wall 34 will not have to form a seal. As aconsequence tolerances employed in'machining these parts may be greatlyrelaxed.

In the embodiment shown in Figure 2, the pump 10 includes a housing 22similar to that in the preferred embodiment;'- This housing 22 mayinclude an enlarged end portion 26 that has a flange 28 to abut againsta wall 14 of the casing 12 and a barrel portion 24 that projects throughan opening 30 in the wall 14 so the the inner end terminates adjacent a.cam 18 inside of the casing 12;

The barrel portion 24 may include a passage 32 that extends axiallyinwardly from the inner end thereof to forman opening in the inner endof the barrel portion.

24. The passage'32 may have a cylindrical side wall 34 and an end wall36 disposed normal to the axis thereof. A supply passage 40 may extendtransversely through the barrel portion 24 to form inlet and outletopenings 42and 44, respectively, onpthe opposite sides of the'barrel.portion 24. A smallpassage 46' may extend axially of the housing 22 sothat one end will intersect the middle of thesu'pply passage 40 and theother end will form an opening 48 in the end wall 36.

A cylindrical plunger 38 may be disposed in the. passage 3250 as toprojectthrough the opening and. en-- gage the periphery 20 of a cam 18-or other. suitable driving means.

The cylindrical passage 32 may have a resilient plug.

58 disposed in the inner end thereof which is of materialsimilar to thatin the. first embodiment. The sides of this plug 61 may be substantiallycylindrical. and of a large enough diameter to fit snugly against thecylindrical side wall 34 of the passage 32. One end 62 of the plug 61may abut the inner end of the plunger 38 while the of the plug 61 willfiowinto the recess 66. Any liquid v in the pumping chamber will be.forced to flow into the small passage '46 and out of the outlet opening.When the. plunger 38 is free to move out of the passage 32,

the plug 61 will expand and return to its free state. The end 64 of theplug 58 will return to a plane and withdraw from the pumping chamber.The liquid will then flow through the inlet opening, the small passage46 and into thepumping chamber.

The embodiment shown in Figure 3 is similar to the v previousembodiments. It includes a housing 22 having 'anenlarged end portion 26that forms a flange 28 to abut against a wall of the casing and a barrelportion 24 that projects through an opening in the wall so the innersubstantially cylindrical side walls 34 and a plane end A fluid wall 36disposed normal to the axis thereof. supply passage 40may extendtransversely through the barrel portion'to form inlet and outletopenings on the opposite sides of the barrel portion 24. A small passage46 may extend axially so that one end communicates with the center ofthe transverse passage 40 while the other end forms an opening 48 in theend wall 36.

A substantially cylindrical plunger 38 may be disposed. in thecylindrical passage 32 so asto projectthroughthe opening and engage theperiphery of a cam 18 or other suitable driving means.

A resilient plug 68 may be disposed in the cylindrical passage 32between the plunger 38 and the end wall 36. The exterior of the plug 68may be cylindrical so as to engage the cylindrical wall 34 of thepassage 32. One end 70 of the plug 68 may abut the inner end of theplunger 33 while the other end engages the end wall 36 of the passage32. This end 78 of the plug 68 may have a recess 72 with a cylindricalside wall 74 and a plane end wall 76 that extends inwardly so as tocooperate with the end wall 36 to form a pumping chamber thatcommunicates with the opening 48 formed by the axial passage 46. Whenthe cam rotates to force the plunger 38 into the passage 32, the plug 68will be compressed. This in turn will cause the volume of the pumpingchamber to be materially reduced. Consequently, any fluid in the chamberwill be forced to fiow through the axial passage 46 and pass through theoutlet opening. When the cam will permit the plunger 38 to move out ofthe passage 32, the resilient action of the plug 68 will bias theplunger 38 against the periphery of the cam. At this time the pumpingchamber will assume its original shape and its volume. Thus the fluidmay be drawn from the inlet into the pumping chamber. In order toincrease the biasing action of the plug 68 and reinforce the side walls74 thereof, a spring 78 may be provided. In the present instance thespring 78 forms a helix that is embedded in the walls 74 of the plug 68.

In the embodiment shown in Figure 4, the pump includes a housing 22having an enlarged end portion 26 that forms a flange 28 to abut againsta wall of the casing and a barrel portion 24 that projects through anopening in the wall so the inner end terminates adjacent a cam inside ofthe casing. A passage 32 may extend inwardly from one end of the barrelportion 24 so as to form an opening in the end thereof. This passage 32may have a cylindrical side wall 34 and an end wall 36 that is disposednormal to the axis of the passage 32. A supply passage 40 may extendtransversely of the barrel portion with the opposite ends thereofforming inlet and outlet openings on the sides of the barrel portion 24.

A passage 46 of reduced diameter may extend axially of the barrelportion 24 so as to form an opening 48 in the end wall 36 and tointersect the center of the supply passage 40. A plunger 38 may bereciprocably disposed in the passage 32 to project through the openingand engage a suitable driving means such as a cam.

A resilient plug 80 may be disposed in the end of the cylindricalpassage 32 with the exterior thereof snugly engaging the side walls 34.This plug 80 may be in the form of a hollow sleeve 81 that has one end82 thereof engaging the plunger 38 and the other end 84 engaging a seat86 formed by a rigid washer-shaped member that engages the end wall. Thepassage 88 in the sleeve may form a pumping chamber that communicateswith the.

opening 48 formed by the small passage 46. Thus as the cam moves theplunger 38 in and out, the sleeve 81 will be compressed and alternatelyincrease and decrease the volume of the pumping chamber.

The embodiments shown in Figures 5 and 6 are substantially identical.They may include a housing 22 having a barrel portion 24, a mountingflange 28 and a plunger 38 reciprocably disposed in the passage 32. Aresilient plug 90 may be disposed in the inner end of the passage 32 toseat on a washer member 86 and engage the side walls and the plunger 38.These plugs 90 may have recesses 92 and 94 therein that form pumpingchambers that communicate with the supply passage 40 by means of a smallpassage 46 and the opening in the washer member 86.

In the embodiment of Figure 5, the recess 92 in the plug 98 comprises acylindrical passage 96: extending inwardly from the end thereof. Thebottom 98 of this passage 96 may comprise a plane surface that isdisposed normal to the axis of the passage 96.

In the embodiment shown in Figure 6, the recess 96 in the plug issemi-spherical and extends part way into the plug 90 to form a pumpingchamber. This chamber communicates with the supply passage. Thus whenthe plunger 38 reciprocates, the fluid will flow from the intake to thepumping chamber and out the outlet.

In theembodiment shown in Figure 7, the pump 10 includes a housing 22having an enlarged end portion that forms a flange to abut against awall of the casing and a barrel portion 24 that projects through anopening in the wall so that the inner end terminates adjacent a caminside of the casing. A passage 102 may extend axially inwardly from theinner end of the barrel portion 24 so as to form an opening in the endadjacent the cam. This passage 182 may include a threaded cylindricalside wall 104 and an end wall 186 disposed normal to the axis thereof. Asupply passage 40 may extend substantially transversely through thebarrel portion 24 and form inlet and outlet openings on the oppositesides thereof. A small axial passage 46 with one end thereofintersecting the center of the supply passage 48 may be provided so thatthe other end thereof forms an opening 48 in the end wall 36 of thepassage 32.

A member 105 with a threaded exterior may be threaded into the passage102 so as to project through the opening and terminate adjacent the cam.The mem-- ber 105 may have a passage 188 that extends axiallytherethrough. This passage 108 may include a cylinof the plug 114 may bea plane disposed normal to the axis of the cone so as to abut the end ofthe plunger 38. The larger end of the cone may have a conical passageextending inwardly therefrom to form a pumping chamber which registerswith the opening formed by the small passage 46. V

In the embodiment shown in Figure 8, the pump 10 includes a housing 22having an enlarged end portion that forms a flange to abut against awall of the casing and a barrel portion 24 that projects through anopening in the wall so that the inner end projects toward a cam disposedinside of the casing. A cylindrical passage 118 may extend inwardly fromthe end of the barrel portion 24 adjacent the cam. A supply passage 40may extend transversely to form inlet and outlet openings on theopposite sides thereof. A small passage 46 may interconnect the end ofthe cylindrical passage 118 with the center of the supply passage 40. Asubstantially cylindrical resilient sleeve 128 may be disposed in thecylindrical passage 118 so that the exterior thereof will form a snugfit against the side walls of the cylindrical passage 118. A passage mayextend through the resilient member 128 with the outer end portion 122thereof being larger in diameter than the smaller end portion 124. Aplunger 38 may be reciprocably disposed in the larger portion 122 sothat it will project therefrom to engage a cam. A resilient plug 126 maybe disposed in the enlarged portion 122 so as to abut the plunger 38 andseat on the shoulder 128 formed by the reduced portion. A recess 138 maybe formed in the end of the plug 126 so as to form a pumping chamberthat registers with the reduced end portion 124. Thus when the plunger38 is driven axially into the passage 122, the capacity of the pumpingchamber will decrease and force the fluid out of the chamber. It shouldbe noted that the use of the resilient sleeve 128 will insure a goodsealing action around the walls of the plunger 38 and the cylindricalpassage 122 thereby greatly relaxing the tolerances required in theproduction of these parts.

Various changes and modifications of the embodiments of'the-inventiondescribed herein may be made bythose skilled in the art withoutdeparting from the spirit and principles of the invention.

What is claimed is:

1. A pump comprising a housing having a passage extending inwardly fromone end thereof to form side and endwalls, a plunger reciprocablydisposed in said passage and slidably engaging said side wall, aresilient plug being wholly' disposed in said passage and abuttinglyengaging said end wall and said plunger, said plug being peripherallysupported by said passage walls, a pumping chamber formed between saidend wall and said plug, and inlet and outlet means communicating withsaid pumping chamber.

2. A pump comprising a housing having a passage extending inwardly fromone end thereofto form a side surface and an end wall, a plungerreciprocably disposed in; said passage, a resilient plug disposed insaid passage to abut the end surface of said plunger, said plug havingan end wall engaging said first mentioned'end wall, at least one of saidwalls having a recess therein to form a pumping chamber, said plugiandsaid chamber b'eiiigpositioned so thatthe pressure insaid chamber willforce the exterior of said plug against said walls and surfaces, andinlet and outlet means communicating with said chamber.

3. A pump comprising'a housing having a passage extending inwardly fromone end thereof to form side andend walls, said side walls including asubstantially cylindrical portion and a tapered portion disposed between said cylindrical portion and said end wall, a substantiallycylindrical plunger reciprocably disposed in said cylindrical portion, aresilient plug disposed in said tapered portion to engage said end walland said plunger, apumping chamber formed between said end wall and saidplug and inlet and outlet means communicating with said pumping chamber.

4. A pump comprising a housing having a passage extending inwardly fromone end thereof to form side and end walls, a plunger reciprocablydisposed in said passage, a resilient plug disposed in said passage toabut said plunger and having an end thereof engaging said end Wall,inlet and outlet means communicating with said passage to form anopening in said end wall, said end of saidplug having a recess with adiameter substantially identical to said opening.

5. A pump comprising a housing having a passage extending inwardly fromone end thereof to form side and end walls, a plunger reciprocablydisposed in said passage, an inlet and outlet passage communicating withsaid passage to form an opening in said end wall, a resilient plugdisposed in said passage between said end wall and said plunger, saidplug having a recess extending inwardly to form side walls engaging saidfirst side wall and form a pumping chamber positioned to registerwithithe opening formed by said inlet and outlet passage.

6'. A pump comprising a housing having a passage extending inwardly fromone end thereof to form side and end walls, a plunger reciprocablydisposed in said passage, an inlet and outlet passage communicating withsaid passage to form an opening in said end wall, a resilient plugdisposed in said passage between said end wall'and'said plunger, saidplug having a recess extending inwardly to form side walls engaging saidfirst side wall and form a pumping chamber positioned to register withthe opening formed by said inlet and outlet passage, and spring meansdisposed in said side walls.

7. A pump comprising a housing having a passage extending inwardly fromone end thereof to form a side wall having a substantially cylindricalportion and an end wall disposed normal to the axis thereof, a plungerreciprocably disposed in said cylindrical portion and having an innerend parallel to said end wall, a resilient plug disposed in saidpassage, said plug having a plane end engaging-'saidend of said plungerand a substantially cylindrical side wallwhic'h forms a pumping chamberopening toward said end wall, and inlet and outlet means communicatingwith said pumping chamber.

8. A pump comprising a housing having a passage extending inwardly fromone end thereof to form side and end walls, a plunger reciprocablydisposed in said passage, a resilient plug disposed in said passagebetween said end wall and said plunger, one end of said plug having asubstantially semispherical recess positioned to cooperate with said endwall to form a pumping chamber, and inlet and outlet means communicatingwith said pumping chamber.

9. A pump comprising a housing having a passage extending inwardly fromone end thereof and forming an end wall, inlet and outlet meanscommunicating with said passage and forming an opening in said end wall,a member disposed within said first passage and having a second passageextending therethrough, said second passage including a'substantiallycylindrical outer portion and a tapering inner portion, a plungerreciprocably disposed in said cylindrical portion, a truncated conicalplug of resilient material'disposed in said tapered portion and havingthe smaller end thereof engage said plunger and the larger end thereofengage said end wall, a pumping chamber formed between said end wall andsaid plug, said inlet and outlet means communicating with said pumpingchamber.

10. A pump comprising a housing having a passage extending inwardly fromone end thereof to form an end wall, a member disposed within saidpassage and having a passage extending'therethrough, said passageincluding a substantially cylindrical outer portion and a divergentlytapered inner portion, a truncated conical plug of resilient materialdisposed in said tapered portion, the small end of said plug engagingthe end of said plunger and the larger end of said plug engaging saidend wall, a recess extending inwardly into said plug from said large endto form a pumping chamber, inlet and outlet means communicating withsaid outlet chamber.

11. A pump comprising a housing having a passage having. an enlargedportion and a reduced portion with an annular shoulder formedtherebetween, a plunger reciprocably disposed in said enlarged portion,a resilient plug disposed in said enlarged portion between said plungerand engaging said shoulder, a recess formed in said plug to form apumping chamber communicating with said reduced portion, and inlet andoutlet means communicating with said reduced portion.

12. A pump comprising a housing having a passage extending inwardly fromone side thereof, said passage having a side wall and an end wall, aplunger reciprocably disposed within said passage and having at least aportion ofthe exterior thereof slidably engaging said side walls, aresilient plug of a compressible elastic material disposed whollywithinand peripherally supported by said passage side wall, the oppositeends of said plug freely engaging the end of said plunger and said endwall, said resilient plug. forming at least one side of a pumpingchamber.

13. A pump'comprising a housing having a passage extending inwardly fromone side thereof, said passage including a side wall with asubstantially cylindrical surface thereofand an end wall having at leasta portion thereof normal to the axis of said cylinder, 21 plungerreciprocably disposed within said passage and having at least a portionofthe exterior thereof slidably engaging said cylindrical surface, aresilient plug of a compressible elastic material disposed wholly withinsaid passage and supported by said side wall, said plug including endwall portions continuously engaging said plunger and said end wall,said'plug and said end wall forming a pumping chamber, said plug beingcompressible as a result of reciprocating movement of said plunger tocause a variation in the capacity of said chamber.

(References on following page) 9 10 References Cited in the file of thispatent FOREIGN PATENTS UNITED STATES PATENTS 438,353 Italy Aug. 6, 19483,315,331; 115101111 July 1(2), 952 508,784 Belgium Feb. 15, 1952 3I'OWHE 2 195 5 09 54 F A 19 1925 2,791,969 Berliner May 14, 1957

